1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    *
5    *
6    *
7    * The contents of this file are subject to the terms of the Liferay Enterprise
8    * Subscription License ("License"). You may not use this file except in
9    * compliance with the License. You can obtain a copy of the License by
10   * contacting Liferay, Inc. See the License for the specific language governing
11   * permissions and limitations under the License, including but not limited to
12   * distribution rights of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.util;
24  
25  /**
26   * <a href="Distance.java.html"><b><i>View Source</i></b></a>
27   *
28   * @author Brian Wing Shun Chan
29   */
30  public class Distance {
31  
32      public static double calculate(double lat1, double lon1,
33                                     double lat2, double lon2) {
34  
35          // Convert from radians to degrees
36  
37          lat1 = (Math.PI * lat1) / 180;
38          lon1 = (Math.PI * lon1) / 180;
39          lat2 = (Math.PI * lat2) / 180;
40          lon2 = (Math.PI * lon2) / 180;
41  
42          double miles =
43              3963.4 *
44              Math.acos(
45                  (Math.sin(lat1) * Math.sin(lat2)) +
46                  (Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2)));
47  
48          return miles;
49      }
50  
51      public static double kmToMiles(double km) {
52          return km * 0.621;
53      }
54  
55      public static double milesToKm(double miles) {
56          return miles / 0.621;
57      }
58  
59  }